System for vehicle noise and vibration reduction

ABSTRACT

A drive module for an electric vehicle having noise, vibration, and harshness counter measures. The drive module includes multiple covers and mass dampeners in order to detune vibration and noise from the cabin of the vehicle.

The present disclosure relates to a power train of an electric vehicle.In particular, a rear drive module (RDM) of a vehicle having noise,vibration and harshness (NVH) countermeasures.

A vehicle may include a rear drive module that comprises one or moreelectric tractions motors configured to drive the wheels of the vehicle.An inverter system may also be provided in the RDM in order to convertD/C power from the main high voltage propulsive battery to A/C power inorder to power the electric traction motors. The RDM may also comprise atransmission or a gearbox for changing the drive ratio between the motorand the vehicle wheels. Noise emitted from the gearbox and/or peak whineemitted by the inverter/traction motors and/or vibration betweencomponents of the vehicle/RDM may reduce passenger comfort and overallsatisfaction of the passengers.

This application discloses a passive noise reduction system configuredto reduce the amount of noise emitted from the RDM by providing acousticdampening and mechanical dampening to reduce vibration.

BRIEF DESCRIPTION OF THE DRAWINGS

The features, aspects, and advantages of the present disclosure willbecome apparent from the following description, and the accompanyingexemplary embodiments shown in the drawings, which are briefly describedbelow.

FIG. 1A is an electric vehicle having a rear drive module.

FIG. 1B is a drive train schematic of the vehicle shown in FIG. 1A.

FIG. 2 is a front side view of an exemplary rear drive module.

FIG. 3 is a back side view of the rear drive module of FIG. 2.

FIG. 4 is a view of the rear drive module of FIG. 2 including covers.

FIG. 5 is a bottom view of the covered rear drive module of FIG. 4.

FIG. 6 is perspective view of the covers shown in FIGS. 4 and 5.

FIG. 7 is a close up and exploded view of the mass dampener system ofthe rear drive module shown in FIG. 2.

FIG. 8 is a sectional view of the mass dampener system.

DETAILED DESCRIPTION

According to one embodiment of the disclosure, a drive module isprovided for a vehicle. The drive module includes at least one electricmotor configured to drive wheels of the vehicle, a gearbox mechanicallyattached to the at least one electric motor. The gearbox is configuredto receive output from the at least one electric motor. An inverter isprovided to provide power for the at least one electric motor from abattery of the vehicle. The drive module includes an acoustic wrapconfigured to dampen noise emitted from the drive module, and a massdampener attached to a motor of the at least one electric motorconfigured to reduce vibration of the drive module.

According to another exemplary embodiment, a vehicle includes a mainpropulsive battery pack. The vehicle further includes a drive module.The drive module includes at least one electric motor configured todrive wheels of the vehicle, a gearbox mechanically attached to the atleast one electric motor, wherein the gearbox is configured to receiveoutput from the at least one electric motor, an inverter configured toprovide power for the at least one electric motor from a battery of thevehicle, an acoustic wrap configured to dampen noise emitted from thedrive module, and a mass dampener attached to a motor of the at leastone electric motor configured to reduce vibration of the drive module.

According to another exemplary embodiment, a rear drive module for adrive train of an electric vehicle is provided. The rear drive moduleincludes a pair of electric motors each configured to drive acorresponding rear wheel of the vehicle, a gearbox mechanically attachedto the at least one electric motor. Wherein the gearbox is configured toreceive output from the pair of electric motors, a pair of inverterscorresponding to each electric motor configured to convert power fromthe battery of the vehicle to corresponding motor of the pair ofelectric motors. A first and second acoustic wrap attached to andcovering a corresponding electric motor of the pair of electric motors.A pair of mass dampeners attached to a corresponding electric motor ofthe pair of electric motors, wherein the mass dampeners configured toreduce vibration of the drive module. Wherein the pair of mass dampenersis attached to corresponding mounting points of the vehicle frame.

FIG. 1A illustrates a vehicle 1 having a high voltage propulsive batteryconnected to a rear drive module (RDM) (not shown; inside the vehicle 1)configured to drive the rear wheels of the vehicle. Although a reardrive module is shown and described for exemplary purposes, the scope ofthe NVH reduction system disclosed herein is not limited to rear drivemodules. The disclosed system may be employed with drive modules for oneor more vehicle wheels, regardless of location of the drive module orthe wheel(s) being driven.

FIG. 1B shows an electric vehicle 1 with the drivetrain 100, theexemplary vehicle includes an internal combustion engine 110, agenerator 4, and electric traction motors 11. The internal combustionengine 110 drives the generator 4 to produce electrical power for abattery 112 and the motors 11. A generator inverter 3 connected to thegenerator 2 may also be provided. A gearbox 12 is configured to providethe required drive ratio for the vehicle. Power to the motors 11 iscommunicated via inverters 10, which transforms DC power provided to theAC power required by the motors 11.

FIGS. 2 and 3 show an exemplary RDM 2 having one or more electrictraction motors 11. Inverters 10 are configured to convert D/C powerfrom the main high voltage propulsive battery (not shown) to A/C powerin order to power the traction motors 11. The traction motors areconnected to a transmission/gearbox 12 for changing the drive ratiobetween the motor and the vehicle wheels. Dampener assemblies 20 may beinserted into each frame of the electric motors 11. The dampenerassembly is configured to act as a mass dampener and reduce thevibration of the RDM 2. Each inverter 10 may be attached tocorresponding electric motor 11, and each electric motor 11 is attachedto the gearbox 12. Thus, the components of RDM 2 are mechanicallyattached to at least the electric motor 11. The mechanism of the massdampener assemblies 20 is explained further below.

FIGS. 4 and 5 shows the RDM 2 having acoustic wraps 13, 14, and 15. Eachcorresponding acoustic wrap 13, 14, and 15 is configured to conform tothe shape of the corresponding component covered by each wrap 13, 14,and 15. For example, the acoustic wrap 13 conforms to the shape ofinverters 10, the acoustic wrap 14 confirms to the shape of the electricmotors 11, and the acoustic wrap 15 conforms to the shape of thetransmission/gearbox 12. Each acoustic wrap includes attachments16/17/18/19 configured to hold the wrap in place onto the correspondingcovered components. Attachment 16 is configured to be attached orfastened onto the inverter cover 13 and structurally support theinverter cover 13. Attachment 16 may also be attached to a portion ofthe electrical motor 11. The attachment 16 may also extend from side toside as shown in FIG. 4 and FIG. 5, where attachment 16 extends from oneside of the inverter cover 13 shown in FIG. 5 to the opposite side ofthe inverter cover shown in FIG. 4. Attachments 19 may include tabs thatprevent the gearbox acoustic wrap 15 from being detached. Theattachments 18 may include a band extending from a side of the gearboxacoustic wrap 15 towards the bottom of the gearbox wrap 15 and ending atthe front of gearbox wrap as shown in FIG. 4. The attachments 17 of theacoustic wrap 14 of the electric motors 11 may also include Velcro (e.g.hook and loop fastener) configured to hold and close the acoustic wrap14 around the electric motors 11.

FIG. 6 shows an isolated view of each wrap 13/14/15. A retainingfastener 30 may be provided to hold the cover 14 to the correspondingmotors 11. Retaining fastener 30 may be a ratchet type fastener (e.g.Christmas tree clip). The retaining fasteners 30 are configured to beinserted into the frame 11 a of the corresponding motor 11. Theattachments 16-19 may be made integral to the corresponding attachedacoustic cover. The attachments 16, 18, and 19 may be attached to thecorresponding elements via Velcro (i.e. hook and loop fasteners) similarto attachment 17. For example, tabs 19 of wrap 15 may be attached ontowrap 14 via Velcro, and endpoints of attachment 16 may include Velcroattachment to its corresponding structure at the end of the attachments.Each acoustic wrap 13/14/15 may include two or more layers of materialsand may include a heavy layer barrier in addition to an lightweightacoustic de-coupler and an anti-abrasive scrim on inner and outersurfaces of the acoustic wraps 13/14/15 to improve handling of thewarps, ward of external contaminants, and improve heat resistance.Materials are chosen for acoustic performance while also managingtemperature requirements and environmental constraints. The wraps13/14/15 encloses all necessary surfaces while leaving adequateventilation for cooling and clearance to moving/rotating parts. Thissystem reduces noise coming from the RDM 2, specifically high frequencynoise (>500 hz). The shape of the wrap 13/14/15 may also accommodate foradditional systems of the RDM 2. For example, the wrap 14 of theelectric motor may accommodate for cooling ports 31 shown in FIGS. 2-5via cutout 14 a. Cutout 14 a allows the warp 14 to accommodate forcooling ports 31 while also allowing the cooling ports 31 to act as alock to prevent the wrap 14 from moving or sliding.

FIG. 7 shows a close up and exploded view of the mass dampener assembly20. The mass dampener assembly 20 may be inserted into a frame 11 a ofthe electric traction motor 11. The dampener assembly includes an insert23, a plate 22, a bolt 24, and a detuning mass 21. Each electric motor11 is configured to be attached to a mounting structure 40 of thevehicle 1. The mounting structure 40 may be an attachment point of thevehicle frame of the vehicle 1. The insert 23 is configured to belocated in an opening 11 b of the electric motor frame 11 a. The plate22 configured to be placed between the insert 23 and the detuning mass21. The head of the bolt 24 is configured to sit inside an opening ofthe detuning mass 21. The plate 22 is configured to support the detuningmass 21. As shown in FIG. 8, this configuration allows the center ofgravity 21 a of the detuning mass 21 to sit further from the structuralfulcrum 25 of the RDM 2. The structural fulcrum 25 is the pivot point ofvibrational movement due to forces from the RDM 2. The mass dampenerassembly 20 is configured to reduce the vibration of RDM 2 relative tothe structural fulcrum. Insert 23 may be flexible and may includesprings 23 a in order to provide vibration detuning via the massdampener 21. The mass dampener assembly 20 added is configured toeffectively increase dynamic stiffness of rear drive module mountingstructure 40, thereby minimizing structure borne noise. The detuningmass 21 is designed such that the fastener length can be minimized. Thecup shape of the detuning mass 21 allows convenient installation andeasy tool access. The cup design also allows the center of gravity ofthe mass 21 a to be distant from the mount location to maximize theeffectiveness of the dampening assembly 20. Insert 23 may also compriseof a rubber material configured to isolate further structural vibrationsof the RDM 2 and mounting structure 40, specifically structural lowfrequency noise. The materials may include a composite sandwich ofmaterials, ordered from the inner layer to outer layer, comprising of anapproximately 0.05 mm thick 30 oz scrim, approximately 7 mm thicklightweight polyurethane foam, approximately 2.5 mm thick heavyweightEVA (Etholyne/Vinyl/Acetate formulation), and approximately 0.05 mmthick 40 z scrim. The lightweight layer should lay closest to the RDM 2,with the heavyweight layer nearer to the outside. Thus the 30 oz scrimlays closest to the RDM 2 while the 40 oz scrim is located the furthest.Although only one side of the RDM 2 is shown in FIG. 2, theconfiguration of mass dampener assembly 20 shown in FIGS. 7 and 8 isalso provided on the other electric motor 11.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the disclosure as recited inthe appended claims.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” etc.) are merely used to describe the orientation ofvarious elements in the FIGURES. It should be noted that the orientationof various elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

It is important to note that the construction and arrangement of theread drive module as shown in the various exemplary embodiments isillustrative only. Although only a few embodiments have been describedin detail in this disclosure, those skilled in the art who review thisdisclosure will readily appreciate that many modifications are possible(e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.) withoutmaterially departing from the novel teachings and advantages of thesubject matter described herein. For example, elements shown asintegrally formed may be constructed of multiple parts or elements, theposition of elements may be reversed or otherwise varied, and the natureor number of discrete elements or positions may be altered or varied.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. Other substitutions,modifications, changes and omissions may also be made in the design,operating conditions and arrangement of the various exemplaryembodiments without departing from the scope of the present disclosure.

What is claimed is:
 1. A drive module for a vehicle comprising: at leastone electric motor configured to drive wheels of the vehicle; a gearboxmechanically attached to the at least one electric motor, wherein thegearbox is configured to receive output from the at least one electricmotor; an inverter configured to provide power for the at least oneelectric motor from a battery of the vehicle; an acoustic wrapconfigured to dampen noise emitted from the drive module; and a massdampener attached to a motor of the at least one electric motorconfigured to reduce vibration of the drive module; wherein the acousticwrap includes an inverter acoustic wrap, configured to be attached toand cover the inverter in order to significantly dampen noise from theinverter.
 2. The drive module of claim 1, wherein the acoustic wrapfurther comprises an electric motor acoustic wrap, configured to beattached to and cover the one motor of at least one electric motor inorder to significantly dampen noise from the one motor.
 3. The drivemodule of claim 2, wherein the electric motor acoustic wrap includes amotor attachment configured to hold the electric motor acoustic wraponto the electric motor and close the acoustic wrap.
 4. The drive moduleof claim 1, wherein the inverter acoustic wrap includes a first inverterattachment configured to hold the acoustic wrap onto the inverter; andwherein the first inverter attachment is fastened onto the inverter. 5.The drive module of claim 4, wherein the inverter acoustic wrap includesa second inverter attachment configured to hold the acoustic wrap ontothe inverter; and wherein the second inverter attachment is fastenedonto the one motor of the at least one electric motor.
 6. The drivemodule of claim 1, wherein the acoustic wrap further includes a gearboxacoustic wrap, configured to be attached to and cover the gearbox inorder to significantly dampen noise from the gearbox.
 7. The drivemodule of claim 6, wherein the gearbox acoustic wrap includes attachmenttabs configured to hold the gearbox acoustic wrap onto the gearbox.
 8. Avehicle comprising: a main propulsive battery; a drive moduleelectrically connected to the battery comprising: at least one electricmotor configured to drive wheels of the vehicle; a gearbox mechanicallyattached to the at least one electric motor, wherein the gearbox isconfigured to receive output from the at least one electric motor; aninverter configured to provide power for the at least one electric motorfrom a battery of the vehicle; an acoustic wrap configured to dampennoise emitted from the drive module; and a mass dampener attached to theat least one electric motor configured to reduce vibration of the drivemodule; and wherein the acoustic wrap includes an inverter acousticwrap, configured to be attached to and cover the inverter in order tosignificantly dampen noise from the inverter.
 9. The vehicle of claim 8,wherein the acoustic wrap further comprises an electric motor acousticwrap, configured to be attached to and cover one motor of at least oneelectric motor in order to significantly dampen noise from the onemotor.
 10. The vehicle of claim 9, wherein the electric motor acousticwrap includes a motor attachment configured to hold the electric motoracoustic wrap onto the electric motor and close the acoustic wrap. 11.The vehicle of claim 8, wherein the inverter acoustic wrap includes afirst inverter attachment configured to hold the acoustic wrap onto theinverter; and wherein the first inverter attachment is fastened onto theinverter.
 12. The vehicle of claim 11, wherein the inverter acousticwrap includes a second inverter attachment configured to hold theacoustic wrap onto the inverter; and wherein the second inverterattachment is fastened onto one motor of the at least one electricmotor.
 13. The vehicle of claim 8, wherein the acoustic wrap furtherincludes a gearbox acoustic wrap, configured to be attached to and coverthe gearbox in order to significantly dampen noise from the gearbox. 14.The vehicle of claim 13, wherein the gearbox acoustic wrap includesattachment tabs configured to hold the gearbox acoustic wrap onto thegearbox.
 15. A drive module for a vehicle comprising: at least oneelectric motor configured to drive wheels of the vehicle; a gearboxmechanically attached to the at least one electric motor, wherein thegearbox is configured to receive output from the at least one electricmotor; an inverter configured to provide power for the at least oneelectric motor from a battery of the vehicle; an acoustic wrapconfigured to dampen noise emitted from the drive module; and a massdampener attached to a motor of the at least one electric motorconfigured to reduce vibration of the drive module; wherein the massdampener comprises: an insert located inside an opening of a frame ofthe one motor of the at least one motor, wherein the insert isconfigured to receive a bolt; a detuning mass directly adjacent a plate,wherein the plate abuts the insert; said bolt extends through thedetuning mass, the plate, and the insert and is configured to beattached to a mounting point of the vehicle at the end of the bolt;wherein the detuning mass is configured to dampen the vibrations of thedrive module.
 16. A rear drive module for a drive train of an electricvehicle: a pair of electric motors each configured to drive acorresponding rear wheel of the vehicle; a gearbox mechanically attachedto the pair of electric motors, wherein the gearbox is configured toreceive output from the pair of electric motors; a pair of inverterscorresponding to each electric motor configured to convert power fromthe battery of the vehicle to corresponding motor of the pair ofelectric motors; a first and second acoustic wrap attached to andcovering a corresponding electric motor of the pair of electric motors;a pair of mass dampeners attached to a corresponding electric motor ofthe pair of electric motors, wherein the mass dampeners configured toreduce vibration of the drive module; and wherein the pair of massdampeners is attached to corresponding mounting points of the vehicleframe.
 17. The rear drive module of claim 16, wherein each of the massdampeners comprises: an insert located inside an opening of acorresponding frame of the pair of electric motors, wherein the insertis configured to receive a bolt; a detuning mass directly adjacent aplate, wherein the plate abuts the insert; said bolt extends through thedetuning mass, the plate, and the insert and is configured to beattached to a corresponding mounting point of the vehicle at the end ofthe bolt; wherein the detuning mass is configured to dampen thevibrations of the rear drive module.